aboutsummaryrefslogtreecommitdiffstats
path: root/kernel/kallsyms.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /kernel/kallsyms.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'kernel/kallsyms.c')
-rw-r--r--kernel/kallsyms.c411
1 files changed, 411 insertions, 0 deletions
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
new file mode 100644
index 000000000000..1627f8d6e0cd
--- /dev/null
+++ b/kernel/kallsyms.c
@@ -0,0 +1,411 @@
+/*
+ * kallsyms.c: in-kernel printing of symbolic oopses and stack traces.
+ *
+ * Rewritten and vastly simplified by Rusty Russell for in-kernel
+ * module loader:
+ * Copyright 2002 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
+ *
+ * ChangeLog:
+ *
+ * (25/Aug/2004) Paulo Marques <pmarques@grupopie.com>
+ * Changed the compression method from stem compression to "table lookup"
+ * compression (see scripts/kallsyms.c for a more complete description)
+ */
+#include <linux/kallsyms.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/seq_file.h>
+#include <linux/fs.h>
+#include <linux/err.h>
+#include <linux/proc_fs.h>
+#include <linux/mm.h>
+
+#include <asm/sections.h>
+
+#ifdef CONFIG_KALLSYMS_ALL
+#define all_var 1
+#else
+#define all_var 0
+#endif
+
+/* These will be re-linked against their real values during the second link stage */
+extern unsigned long kallsyms_addresses[] __attribute__((weak));
+extern unsigned long kallsyms_num_syms __attribute__((weak,section("data")));
+extern u8 kallsyms_names[] __attribute__((weak));
+
+extern u8 kallsyms_token_table[] __attribute__((weak));
+extern u16 kallsyms_token_index[] __attribute__((weak));
+
+extern unsigned long kallsyms_markers[] __attribute__((weak));
+
+static inline int is_kernel_inittext(unsigned long addr)
+{
+ if (addr >= (unsigned long)_sinittext
+ && addr <= (unsigned long)_einittext)
+ return 1;
+ return 0;
+}
+
+static inline int is_kernel_text(unsigned long addr)
+{
+ if (addr >= (unsigned long)_stext && addr <= (unsigned long)_etext)
+ return 1;
+ return in_gate_area_no_task(addr);
+}
+
+static inline int is_kernel(unsigned long addr)
+{
+ if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
+ return 1;
+ return in_gate_area_no_task(addr);
+}
+
+/* expand a compressed symbol data into the resulting uncompressed string,
+ given the offset to where the symbol is in the compressed stream */
+static unsigned int kallsyms_expand_symbol(unsigned int off, char *result)
+{
+ int len, skipped_first = 0;
+ u8 *tptr, *data;
+
+ /* get the compressed symbol length from the first symbol byte */
+ data = &kallsyms_names[off];
+ len = *data;
+ data++;
+
+ /* update the offset to return the offset for the next symbol on
+ * the compressed stream */
+ off += len + 1;
+
+ /* for every byte on the compressed symbol data, copy the table
+ entry for that byte */
+ while(len) {
+ tptr = &kallsyms_token_table[ kallsyms_token_index[*data] ];
+ data++;
+ len--;
+
+ while (*tptr) {
+ if(skipped_first) {
+ *result = *tptr;
+ result++;
+ } else
+ skipped_first = 1;
+ tptr++;
+ }
+ }
+
+ *result = '\0';
+
+ /* return to offset to the next symbol */
+ return off;
+}
+
+/* get symbol type information. This is encoded as a single char at the
+ * begining of the symbol name */
+static char kallsyms_get_symbol_type(unsigned int off)
+{
+ /* get just the first code, look it up in the token table, and return the
+ * first char from this token */
+ return kallsyms_token_table[ kallsyms_token_index[ kallsyms_names[off+1] ] ];
+}
+
+
+/* find the offset on the compressed stream given and index in the
+ * kallsyms array */
+static unsigned int get_symbol_offset(unsigned long pos)
+{
+ u8 *name;
+ int i;
+
+ /* use the closest marker we have. We have markers every 256 positions,
+ * so that should be close enough */
+ name = &kallsyms_names[ kallsyms_markers[pos>>8] ];
+
+ /* sequentially scan all the symbols up to the point we're searching for.
+ * Every symbol is stored in a [<len>][<len> bytes of data] format, so we
+ * just need to add the len to the current pointer for every symbol we
+ * wish to skip */
+ for(i = 0; i < (pos&0xFF); i++)
+ name = name + (*name) + 1;
+
+ return name - kallsyms_names;
+}
+
+/* Lookup the address for this symbol. Returns 0 if not found. */
+unsigned long kallsyms_lookup_name(const char *name)
+{
+ char namebuf[KSYM_NAME_LEN+1];
+ unsigned long i;
+ unsigned int off;
+
+ for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
+ off = kallsyms_expand_symbol(off, namebuf);
+
+ if (strcmp(namebuf, name) == 0)
+ return kallsyms_addresses[i];
+ }
+ return module_kallsyms_lookup_name(name);
+}
+EXPORT_SYMBOL_GPL(kallsyms_lookup_name);
+
+/*
+ * Lookup an address
+ * - modname is set to NULL if it's in the kernel
+ * - we guarantee that the returned name is valid until we reschedule even if
+ * it resides in a module
+ * - we also guarantee that modname will be valid until rescheduled
+ */
+const char *kallsyms_lookup(unsigned long addr,
+ unsigned long *symbolsize,
+ unsigned long *offset,
+ char **modname, char *namebuf)
+{
+ unsigned long i, low, high, mid;
+ const char *msym;
+
+ /* This kernel should never had been booted. */
+ BUG_ON(!kallsyms_addresses);
+
+ namebuf[KSYM_NAME_LEN] = 0;
+ namebuf[0] = 0;
+
+ if ((all_var && is_kernel(addr)) ||
+ (!all_var && (is_kernel_text(addr) || is_kernel_inittext(addr)))) {
+ unsigned long symbol_end=0;
+
+ /* do a binary search on the sorted kallsyms_addresses array */
+ low = 0;
+ high = kallsyms_num_syms;
+
+ while (high-low > 1) {
+ mid = (low + high) / 2;
+ if (kallsyms_addresses[mid] <= addr) low = mid;
+ else high = mid;
+ }
+
+ /* search for the first aliased symbol. Aliased symbols are
+ symbols with the same address */
+ while (low && kallsyms_addresses[low - 1] == kallsyms_addresses[low])
+ --low;
+
+ /* Grab name */
+ kallsyms_expand_symbol(get_symbol_offset(low), namebuf);
+
+ /* Search for next non-aliased symbol */
+ for (i = low + 1; i < kallsyms_num_syms; i++) {
+ if (kallsyms_addresses[i] > kallsyms_addresses[low]) {
+ symbol_end = kallsyms_addresses[i];
+ break;
+ }
+ }
+
+ /* if we found no next symbol, we use the end of the section */
+ if (!symbol_end) {
+ if (is_kernel_inittext(addr))
+ symbol_end = (unsigned long)_einittext;
+ else
+ symbol_end = all_var ? (unsigned long)_end : (unsigned long)_etext;
+ }
+
+ *symbolsize = symbol_end - kallsyms_addresses[low];
+ *modname = NULL;
+ *offset = addr - kallsyms_addresses[low];
+ return namebuf;
+ }
+
+ /* see if it's in a module */
+ msym = module_address_lookup(addr, symbolsize, offset, modname);
+ if (msym)
+ return strncpy(namebuf, msym, KSYM_NAME_LEN);
+
+ return NULL;
+}
+
+/* Replace "%s" in format with address, or returns -errno. */
+void __print_symbol(const char *fmt, unsigned long address)
+{
+ char *modname;
+ const char *name;
+ unsigned long offset, size;
+ char namebuf[KSYM_NAME_LEN+1];
+ char buffer[sizeof("%s+%#lx/%#lx [%s]") + KSYM_NAME_LEN +
+ 2*(BITS_PER_LONG*3/10) + MODULE_NAME_LEN + 1];
+
+ name = kallsyms_lookup(address, &size, &offset, &modname, namebuf);
+
+ if (!name)
+ sprintf(buffer, "0x%lx", address);
+ else {
+ if (modname)
+ sprintf(buffer, "%s+%#lx/%#lx [%s]", name, offset,
+ size, modname);
+ else
+ sprintf(buffer, "%s+%#lx/%#lx", name, offset, size);
+ }
+ printk(fmt, buffer);
+}
+
+/* To avoid using get_symbol_offset for every symbol, we carry prefix along. */
+struct kallsym_iter
+{
+ loff_t pos;
+ struct module *owner;
+ unsigned long value;
+ unsigned int nameoff; /* If iterating in core kernel symbols */
+ char type;
+ char name[KSYM_NAME_LEN+1];
+};
+
+/* Only label it "global" if it is exported. */
+static void upcase_if_global(struct kallsym_iter *iter)
+{
+ if (is_exported(iter->name, iter->owner))
+ iter->type += 'A' - 'a';
+}
+
+static int get_ksymbol_mod(struct kallsym_iter *iter)
+{
+ iter->owner = module_get_kallsym(iter->pos - kallsyms_num_syms,
+ &iter->value,
+ &iter->type, iter->name);
+ if (iter->owner == NULL)
+ return 0;
+
+ upcase_if_global(iter);
+ return 1;
+}
+
+/* Returns space to next name. */
+static unsigned long get_ksymbol_core(struct kallsym_iter *iter)
+{
+ unsigned off = iter->nameoff;
+
+ iter->owner = NULL;
+ iter->value = kallsyms_addresses[iter->pos];
+
+ iter->type = kallsyms_get_symbol_type(off);
+
+ off = kallsyms_expand_symbol(off, iter->name);
+
+ return off - iter->nameoff;
+}
+
+static void reset_iter(struct kallsym_iter *iter, loff_t new_pos)
+{
+ iter->name[0] = '\0';
+ iter->nameoff = get_symbol_offset(new_pos);
+ iter->pos = new_pos;
+}
+
+/* Returns false if pos at or past end of file. */
+static int update_iter(struct kallsym_iter *iter, loff_t pos)
+{
+ /* Module symbols can be accessed randomly. */
+ if (pos >= kallsyms_num_syms) {
+ iter->pos = pos;
+ return get_ksymbol_mod(iter);
+ }
+
+ /* If we're not on the desired position, reset to new position. */
+ if (pos != iter->pos)
+ reset_iter(iter, pos);
+
+ iter->nameoff += get_ksymbol_core(iter);
+ iter->pos++;
+
+ return 1;
+}
+
+static void *s_next(struct seq_file *m, void *p, loff_t *pos)
+{
+ (*pos)++;
+
+ if (!update_iter(m->private, *pos))
+ return NULL;
+ return p;
+}
+
+static void *s_start(struct seq_file *m, loff_t *pos)
+{
+ if (!update_iter(m->private, *pos))
+ return NULL;
+ return m->private;
+}
+
+static void s_stop(struct seq_file *m, void *p)
+{
+}
+
+static int s_show(struct seq_file *m, void *p)
+{
+ struct kallsym_iter *iter = m->private;
+
+ /* Some debugging symbols have no name. Ignore them. */
+ if (!iter->name[0])
+ return 0;
+
+ if (iter->owner)
+ seq_printf(m, "%0*lx %c %s\t[%s]\n",
+ (int)(2*sizeof(void*)),
+ iter->value, iter->type, iter->name,
+ module_name(iter->owner));
+ else
+ seq_printf(m, "%0*lx %c %s\n",
+ (int)(2*sizeof(void*)),
+ iter->value, iter->type, iter->name);
+ return 0;
+}
+
+static struct seq_operations kallsyms_op = {
+ .start = s_start,
+ .next = s_next,
+ .stop = s_stop,
+ .show = s_show
+};
+
+static int kallsyms_open(struct inode *inode, struct file *file)
+{
+ /* We keep iterator in m->private, since normal case is to
+ * s_start from where we left off, so we avoid doing
+ * using get_symbol_offset for every symbol */
+ struct kallsym_iter *iter;
+ int ret;
+
+ iter = kmalloc(sizeof(*iter), GFP_KERNEL);
+ if (!iter)
+ return -ENOMEM;
+ reset_iter(iter, 0);
+
+ ret = seq_open(file, &kallsyms_op);
+ if (ret == 0)
+ ((struct seq_file *)file->private_data)->private = iter;
+ else
+ kfree(iter);
+ return ret;
+}
+
+static int kallsyms_release(struct inode *inode, struct file *file)
+{
+ struct seq_file *m = (struct seq_file *)file->private_data;
+ kfree(m->private);
+ return seq_release(inode, file);
+}
+
+static struct file_operations kallsyms_operations = {
+ .open = kallsyms_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = kallsyms_release,
+};
+
+static int __init kallsyms_init(void)
+{
+ struct proc_dir_entry *entry;
+
+ entry = create_proc_entry("kallsyms", 0444, NULL);
+ if (entry)
+ entry->proc_fops = &kallsyms_operations;
+ return 0;
+}
+__initcall(kallsyms_init);
+
+EXPORT_SYMBOL(__print_symbol);

Privacy Policy